Dimpled joint for guidewire

Abstract

To provide a guidewire for advancing an endoluminal device such as a stent delivery catheter, a balloon expansion catheter and a plaque resection catheter in the lumen.SOLUTION: A guidewire 150 for use in intravascular procedures has a solder or weld joint 156 at a distal end thereof. A plurality of dimples are formed on the surface of the solder / weld joint to increase the engagement and penetration of fibrous material including chronic total occlusions (CTO).SELECTED DRAWING: Figure 11B

Description

Technical Field

[0001] The present invention relates to the field of guidewires for advancing intraluminal devices, such as stent delivery catheters, balloon dilation catheters, and atherectomy catheters, within a body lumen.

Background Art

[0002] In a typical coronary artery surgery, a guiding catheter having a pre-formed distal tip is percutaneously introduced into a peripheral artery of a patient, such as the femoral or brachial artery, using the conventional Seldinger method, and advanced therein until the distal tip of the guiding catheter is positioned at a desired coronary artery ostium. There are two basic techniques for advancing a guide wire into a desired position within the anatomical structure of a patient's coronary artery. The first is the preload technique mainly used for over-the-wire (OTW) devices, and the second is the bare wire technique mainly used for rapid exchange type systems. When using the preload technique, the guide wire is positioned within the lumen of an OTW device, such as an expansion catheter or a stent delivery catheter, with the distal tip of the guide wire just proximal to the distal tip of the catheter, and then both are advanced through the guiding catheter to its distal end. The guide wire is first advanced out of the distal end of the guiding catheter and into the vasculature of the patient's coronary artery until the distal end of the guide wire passes through the arterial position where the intervention is to be performed, such as the lesion to be expanded or the expanded area where the stent is to be deployed. A catheter slidably mounted on the guide wire is advanced out of the guiding catheter and through the previously introduced guide wire into the anatomical structure of the patient's coronary artery until the surgical portion of the intravascular device, such as the balloon of the expansion catheter or the stent delivery catheter, is properly positioned across the arterial position. Once the surgical means is positioned within the desired arterial position and the catheter is in place, the intervention is performed. The catheter can then be removed from the patient through the guide wire. Usually, the guide wire is left in place for a period of time after the procedure is completed to ensure re-access to the arterial position. For example, when arterial occlusion occurs due to the collapse of the incised endothelium, a rapid exchange type perfusion balloon catheter can be advanced through the guide wire in place to inflate the balloon to open the arterial passage and allow blood to be perfused distally through the distal portion of the catheter until the incised portion re-adheres to the arterial wall by natural healing.

[0003] When using the bare wire technique, first advance only the guide wire through the guiding catheter until the distal tip of the guide wire extends beyond the arterial location where the procedure is to be performed. Next, attach a rapid exchange (RX) catheter to the proximal portion of the guide wire that extends from the proximal end of the guiding catheter outside the patient's body. Advance the catheter over the guide wire while the position of the guide wire is fixed until the surgical means on the RX catheter are positioned within the arterial location where the procedure is to be performed. After the procedure, the intravascular device may be removed from the patient over the guide wire, or the guide wire may be further advanced within the coronary anatomy for further procedures.

[0004] Conventional guide wires for angioplasty, stent delivery, atherectomy and other vascular procedures typically comprise an elongate core member having one or more tapered portions near its distal end, and a flexible body such as a helical coil or a tubular body made of a polymeric material disposed around the distal portion of the core member. A formable member, which may be the distal end of the core member or a separate formed ribbon fixed to the distal end of the core member, extends through the flexible body and is fixed to the distal end of the flexible body forming a rounded distal tip by soldering, brazing or welding. Torque applying means are provided at the proximal end of the core member for rotating the guide wire while it is being advanced through the patient's vasculature and thereby manipulating it.

[0005] In certain procedures, such as when delivering a stent around a difficult take-off, e.g., a shepherd's crook-shaped portion, a meandering portion, or a highly angulated portion, substantially more support from a guidewire and / or straightening of the blood vessel is often required than can be provided by a conventional guidewire. Guidewires that provide improved distal support over conventional guidewires have been commercially introduced for such procedures, but such guidewires are not very maneuverable and, in some cases, are very stiff, such that advancing a stent therethrough can risk damaging the blood vessel endothelium. What has been needed but heretofore unavailable is a guidewire that provides a high level of distal support with acceptable maneuverability and a low risk of damage when advanced through a patient's vasculature.

[0006] Also, as discussed above, conventional guidewires that use a tapered distal core can be difficult to use in many clinical situations because they have a sharp change in stiffness along the length of the guidewire, particularly where the taper begins and ends. When a guidewire having a core with a sharp change in stiffness moves through a patient's meandering vasculature, the physician moving the guidewire may feel a sharp resistance when the change in stiffness deviates from the curvature of the patient's vasculature. The sharp change in resistance felt by the physician can interfere with the physician's ability to advance the guidewire safely and controllably through the vasculature. What is needed is a guidewire that does not have a sharp change in stiffness, particularly in the distal portion where it is bent within the vasculature and the guiding catheter. The present invention meets these and other needs by providing distal tip integrity, kink resistance, improved torque response, improved distal tip radiopacity, and a smooth transition region. SUMMARY OF THE INVENTION

[0007] In one embodiment of the present invention, the guide wire has a radiopaque inner coil and a substantially non-radiopaque outer coil. The inner coil and the outer coil are attached to the distal end of the guide wire, and the outer coil covers the inner coil and extends proximally along the guide wire proximal to the proximal end of the inner coil. The inner coil is formed of a radiopaque material so that a physician can easily detect the position of the distal end of the guide wire by fluoroscopy during the procedure. The inner coil and the outer coil may each be formed of one wire or a plurality of wires.

[0008] In another embodiment, a mold is used to form a solder distal tip or a solder joint at the distal end of the guide wire. The solder distal tip attaches together the distal end of the guide wire and the distal ends of the inner coil and the outer coil (if present). It is important that the solder distal tip be uniform from one guide wire to the next and repeatable in its structural formation. A mold including a split mold provides a bullet-shaped solder tip or a micro-J-shaped tip at the distal end of the guide wire to attach the inner and outer coils to the guide wire. Other shaped solder tips are conceivable, such as a solder joint having a conical shape, a truncated conical shape, and a rough surface.

[0009] In another embodiment, a laser is used to form dimples on the surface of the solder joint that connects the distal ends of the guide wires. The laser is used to form dimples at the distal end of the solder joint such that the dimples resemble the dimples on the surface of a golf ball and may have a specific spacing and pattern. The laser can be programmed to provide dimples that are spaced apart from each other and have a specific diameter and depth in response to the user's requirements.

[0010] In another embodiment, the guide wire of the present invention enhances the torque property of the guide wire by using coils with different cross-sectional shapes, without adversely affecting the bending rigidity and functionality of the guide wire. For example, different cross-sectional shapes of the coil can include I-beam shape, vertical rectangle, vertical ellipse, square, peanut shape, vertical hexagon, horizontal hexagon, and horizontal ellipse cross-sections. Considering the constraints due to manufacturing, dimensions, and tolerances, I-beam shape, peanut shape, vertical rectangle, and vertical ellipse cross-sections are preferred over the conventional round cross-section coils to enhance the torque property without adversely affecting the bending rigidity of the guide wire. Coils with different cross-sectional shapes can be used to form single-strand coils or multi-strand coils.

[0011] In another embodiment, a micro J shape is formed at the distal tip of the guide wire by a guide wire tip forming tool. The forming tool is provided to the physician together with the guide wire so that the physician can select the amount of bending at the distal end of the guide wire using the forming tool. Conventionally, the physician bends the distal end of the guide wire by hand, which lacks control over the bending angle and shape. The forming tool includes many cavities with different angular orientations and depths so that the physician can select the bending length and bending angle at the distal tip of the guide wire. The forming tool is spring-biased towards an open position so that the distal end of the guide wire can be inserted into the cavity. Once the guide wire is inserted into the cavity, the physician gently pushes the end of the forming tool to overcome the spring force and move the inner tube with the cavity relative to the outer tube to form a bend at the distal tip of the guide wire. The cavities with a predetermined angle and length provide a consistent micro J shape for the physician to use.

[0012] In another embodiment of the present invention, the distal portion of the guidewire has a reduced cross-section in order to be more flexible when navigating tortuous blood vessels. In this embodiment, the parabolic distal portion of the guidewire includes a significant portion of the distal portion that is ground to form a continuous taper. The continuous taper is formed by a parabolic grind along the distal portion of the guidewire. The parabolic grind provides a smooth, curvilinear transition along the distal portion of the guidewire that maintains a linear change in stiffness while being very flexible, thereby providing the physician with excellent torque and tactile feedback when advancing the guidewire through tortuous anatomical structures.

Brief Description of the Drawings

[0013]

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Best Mode for Carrying Out the Invention

[0014] Prior Art Guide Wire Prior art guide wires typically comprise an elongate core wire having a flexible atraumatic distal end. The prior art guide wire is shown in FIG. 1 and comprises an elongate core member 11 having a proximal core portion 12, a distal core portion 13 and a flexible body member 14 fixed to the distal core portion. The distal core portion 13 has a tapered segment 15, a flexible segment 16 adjacent distally to the tapered segment 15, a distal end 13a and a proximal end 13b. The distal portion 13 also has two or more tapered segments 15 having a typical distally decreasing taper with a substantially round cross-section.

[0015] The core member 11 may be formed from stainless steel, NiTi alloy, or a combination thereof. The core member 11 is optionally coated with a lubricious coating of a fluoropolymer that extends the length of the proximal core, such as Teflon® available from DuPont. A hydrophilic coating may also be used. The length and diameter of the prior art guide wire 10 may be varied according to the particular procedure for which it is intended and the material of which it is constructed. The length of the guide wire 10 is generally in the range of about 65 cm to about 320 cm, more typically about 160 cm to about 200 cm, preferably about 175 cm to about 190 cm, due to the anatomy of the coronary arteries. The diameter of the guide wire is generally in the range of about 0.008 inches to about 0.035 inches (0.203 - 0.889 mm), more typically about 0.012 inches to about 0.018 inches (0.305 - 0.547 mm), preferably about 0.014 inches (0.336 mm), due to the anatomy of the coronary arteries.

[0016] The flexible segment 16 terminates at the distal end 18. The flexible body member 14, preferably a coil, surrounds a portion 13 of the distal end of the elongate core with the distal end 19 of the flexible body member 14 fixed to the distal end 18 of the flexible segment 16 by a solder body 20. The proximal end 22 of the flexible body member 14 is similarly joined or fixed to the distal core portion 13 by a solder body 23. Materials and structures other than solder may be used to join the flexible body 14 to the distal core portion 13, and the term "solder body" includes other materials such as polymeric adhesives including brazing, epoxy, cyanoacrylate, and the like.

[0017] The wire for fabricating the flexible body 14 generally has a transverse diameter of about 0.001 to about 0.004 inches, preferably about 0.002 to about 0.003 inches (0.05 mm). The flexibility may be further enhanced by increasing the number of turns at the distal portion of this coil. This coil may have substantially the same diameter, i.e., cross-sectional dimension, as the proximal core 12. The flexible member 14 may have a length of about 2 to about 40 cm or more, preferably about 2 to about 10 cm. The flexible member 14 in the form of a coil may be formed from a suitable radiopaque material such as platinum or its alloy, or may be formed from other materials such as stainless steel and coated with a radiopaque material such as gold.

[0018] The flexible segment 16 typically has a length in the range of about 1 to about 12 cm, preferably about 2 to about 10 cm, although longer segments may be used. The tapered form of the flexible segment 16 provides for controlled longitudinal deformation and a transition in the flexibility (i.e., degree of rigidity) of the core segment. The flexible segment is adjacent to the core member 11 and is disposed distally on the distal portion 13 to function as a formable member.

[0019] Guide wire having a radiopaque inner coil Based on the present invention, in one embodiment shown in FIGS. 2 to 6, the guide wire 30 has an elongated core member 32 having a proximal core 34 and a distal core 36. The distal core 36 preferably has a tapered shape and has a tapered segment 38 that tapers to a smaller diameter from the proximal end 40 of the guide wire towards the distal end 42 of the guide wire. The elongated core member 32 is preferably formed from stainless steel, although it may be formed from other metals or metal alloys known in the art.

[0020] To improve radiopacity, the guidewire 30 shown in FIGS. 2-6 includes a radiopaque inner coil 44 positioned at its distal end 42 over an elongate core member. The inner coil 44 may be 3 cm in length and may have a distal end 46 that abuts the distal end 42 of the elongate core member 32. 3 cm is a preferred length for the radiopaque inner coil 44, but the length of the inner coil 44 may range from 0.5 cm to 15 cm as needed to meet the physician's requirements. The radiopaque inner coil 44 has a proximal end 48 having a plurality of coils 50 consisting of wires extending from the proximal end 48 to the distal end 46. The radiopaque inner coil 44 is made of a radiopaque material selected from the group of radiopaque metals including platinum (Pt), palladium (Pd), iridium (Ir), tungsten (W), tantalum (Ta), rhenium (Re), and gold (Au). In one embodiment shown in FIG. 2, the radiopaque inner coil 44 is formed from a single coil 50, the diameter of which can be varied as needed for a balance of radiopacity, flexibility, torqueability, and kink resistance (durability). In another embodiment shown in FIG. 3, the radiopaque inner coil 44 is formed from a four-wire coil 52. The four-wire coil 52 consisting of wires can be made using DFT (Drawn Filled Tubing) known in the prior art (a tube filled with or sandwiched by a radiopaque material). The inner coil 44 may be formed using any number of wires, such as the eight-wire coil shown in FIGS. 4A and 4B. In one embodiment, the eight-wire coil of FIGS. 4A and 4B is 31 cm in length, has an outer diameter of 0.0135 ± 0.0005 inches, an inner diameter of 0.0095 inches, a pitch of 0.193 inches, a wire diameter of 0.002 inches, and a spacing between segments of the eight wires of 25% of the wire diameter. These dimensions are representative and can be varied according to different requirements.Importantly, all of the various coil shapes may be formed from the radiopaque metals listed herein such that the radiopaque inner coil 44 is radiopaque and can be easily visualized by a physician using fluoroscopy.

[0021] The embodiments in FIGS. 2-6 also include a non-radiopaque outer coil 56 having an inner diameter 58 that is greater than the outer diameter 60 of the radiopaque inner coil 44 and greater than the outer diameter of the elongate core member 32. The non-radiopaque outer coil 56 is formed from a non-radiopaque material including stainless steel (SS), cobalt-chromium (CoCr), and nickel-titanium (NiTi) alloys. The non-radiopaque outer coil may have a length ranging from 10 cm to 60 cm from the distal end 62 to the proximal end 64. In one embodiment, the non-radiopaque outer coil 56 is 30 cm in length.

[0022] As most clearly shown in FIG. 2, the distal end 46 of the radiopaque inner coil 44, the distal end 42 of the guide wire 30, and the distal end 62 of the non-radiopaque outer coil 56 are all connected together by soldering, adhesive, welding, or brazing. Preferably, the solder ball 66 is formed at the distal end 42 of the guide wire 30 in a known manner for connecting the radiopaque inner coil 44 to the non-radiopaque outer coil 56 and the distal end 42 of the guide wire. The distal end 46 of the radiopaque inner coil 44 preferably does not contact the distal end 62 of the non-radiopaque outer coil 56, and they are connected together by the solder ball 66, but it is important to emphasize that they can be directly connected to each other after the solder ball 66 is formed. The distal end 46 of the radiopaque inner coil 44 does not contact the distal end 42 of the elongate core member 32. The proximal end 48 of the radiopaque inner coil 44 is connected to the elongate core member 32 by a known method, such as a first solder joint 70, welding, adhesive, or brazing. The proximal end 48 of the radiopaque inner coil 44 is not attached to the non-radiopaque outer coil 56. The proximal end 64 of the non-radiopaque outer coil 56 is attached to the elongate core member 32 by a known method, such as a second solder joint 72, welding, adhesive, or brazing. The first solder joint 70 is proximal to the solder ball 66 and distal to the second solder joint 72. The proximal end 64 of the non-radiopaque outer coil 56 is not connected to any part of the radiopaque inner coil 44, thereby providing a seamless outer surface 68 along the non-radiopaque outer coil 56 that does not have a solder joint with the radiopaque inner coil that would cause a rigidity problem. Preferably, as shown in FIG. 2, there are no gaps between the elongate core member 32, the inner coil 44, and the outer coil 56, and there are no gaps between the inner coil 44 and the outer coil 56. Like the radiopaque inner coil 44, the non-radiopaque outer coil 56 may be formed from any number of coils, such as a single-strand coil 50, a four-strand coil 56 (FIG. 3), or an eight-strand coil shown in FIGS. 4A and 4B.

[0023] As shown in the graph of FIG. 5, experiments were conducted to determine the effect of the multi-strand coil on torque. In FIG. 5, straight torque was measured for a guide wire having only an inner and outer coil of one strand, guide wires having inner and outer coils of 4, 6, and 8 strands, and inner and outer coils laser cut in the form of a vertical rectangle. As can be seen in FIG. 5, the single-strand coil and multi-strand coil of the present invention are preferably compared in terms of torque performance.

[0024] As shown in FIG. 6, tests were also conducted to measure the radiopacity of the guide wire of the present invention. The guide wires of Groups 1-6 have the radiopaque inner coil and non-radiopaque outer coil disclosed in FIG. 2. The radiopacity of the radiopaque inner coil is comparable when compared to a commercially available WHISPER® guide wire sold by Abbott Cardiovascular Systems (Santa Clara, Calif.) preferably by fluoroscopy.

[0025] In one embodiment shown in FIG. 2, the proximal portion 74 of the guide wire 30 has a silicone-based hydrophobic coating and a polytetrafluoroethylene (PTFE) coating. The distal portion 76 has a polyvinylpyrrolidone (PVP) hydrocoat coating. Typically, the distal end 42 of the guide wire 30 is not coated.

[0026] Die for forming a solder distal tip Guide wires are available in many different configurations, all including a tip load, support profile, and construction material selected by the physician for a particular clinical case requirement. For certain situations, it has been recognized that a guide wire distal tip having a particular geometry provides the physician with a mechanical advantage when navigating a tortuous path or occluded segment. In this embodiment, the properties of the molten solder flow are overcome to contain the molten solder flow within a predetermined shape. Currently, the solder joint is formed at the distal tip of a guide wire that attaches an elongated core wire to an outer coil. This solder joint is formed using a conventional soldering iron to heat the solder and flow it over the core wire and secure the coil to the core wire when it solidifies. The present invention enables achieving a particular shape by fabricating a soldered tip by different means and casting the molten solder into a predetermined shape.

[0027] As shown in FIGS. 7A - 10B, a mold 80 is used to cast a soldered tip that overcomes many of the obstacles in both cost and manufacturability. By using the mold 80 to form a predetermined soldered shape, not only is the intended geometry of the solder joint obtained, but also the solder joint necessary to attach the elongated core wire of the guide wire to the outer coil is performed (see, for example, FIGS. 2 - 6). This mold can be easily machined to the same position as the bullet-shaped tip 82 or machined to include a small angle feature to what is called a micro-J-shaped tip 84. Utilizing the mold 80 for this soldering tip operation gives the technical team the ability to change the configuration to suit the requirements of the product being fabricated.

[0028] The mold 80 is made as a solid mold constructed of ceramic or other suitable material that can withstand the temperature required to accept the molten solder. The mold 80 has a cavity 86 that accepts the molten solder, the distal tip of the elongated core wire of the guide wire, and, if present, the distal end of the coil. The shape of the cavity 86 determines the shape of the solder joint, such as the bullet-shaped tip 82 and the micro-J-shaped tip 84.

[0029] More complex shapes are achieved by utilizing a split mold 90, where the first shell 92 and the second shell 94 are held together while the solder is molten and then separated to remove the solder tip 88 from the mold. The split mold 90 has the configuration of the solder tip 88 machined on the first face 96 and a mirror image machined on the second face 98. The split mold 90 can be machined to have a bullet-shaped tip 82 or to include small-angle features to form a micro-J-shaped tip 84. Various other solder tip 88 shapes, such as conical, truncated conical, and roughened surfaces, can be formed by the split mold 90.

[0030] A method for forming the solder tip 88 includes placing the mold in a heating device and enabling the solder to become molten. Once molten, the distal tip of the elongated core wire of the guide wire is immersed into the cavity 86 of the mold to enable the solder to flow over the distal tip and the first few turns of the outer coil (if present). A heat transfer body can be placed around segments of the outer coil directly above the cavity 86 of the mold to prevent the solder from flowing to unwanted locations and to control the precise placement of the solder tip 88. Once the solder has flowed into the designated area, the split mold 90 is rapidly cooled to solidify the solder and enable joining of the distal tip of the guide wire and the coil together. Once cooled, that portion can be removed from the mold 80, or alternatively, the first and second shells 92, 94 can be separated and the solder tip 88 removed.

[0031] Utilizing the mold 80 to form the solder tip 88 gives the technical team the ability to quickly change the configuration for the product being fabricated.

[0032] Furthermore, the first face 96 and the second face 98 can be modified to provide several types of features or textures according to the requirements of a particular product determined by its use. The mold 80 can have several forms of texture or even grooves (either raised or recessed) in order to allow for a particular outer surface geometry as required for the specified product requirements. For example, as shown in FIGS. 9A - 9C, the split mold 90 has an angled groove 100 formed in the cavity 86 of the mold such that the soldering tip 88 has a corresponding angled groove 102.

[0033] Most guidewires use solder to form a bonded state at the distal tip and connect the coils, although some guidewires may use epoxy or another similar material instead of solder. The above description with respect to FIGS. 7A - 10B regarding the soldering tip 88 also applies to other suitable metals and epoxies.

[0034] Laser for forming a dimpled joint Generally, most commercially available guidewires have a guidewire tip made of solder material or welding material and have a smooth dome-shaped surface. Such guidewires face difficulties when used to pass through calcified and fibrous tissues to treat chronic total occlusion (CTO). Certain commercially available guidewires are designed to have a higher tip load in order to treat CTO and penetrate complex and stenotic lesions. Optimal wire strength, tip load, and tip shape assist in the pushability and manipulation of the guidewire through the lesion, but when using a smooth tip surface, there is likely a problem of engaging with calcified and fibrous tissues, thereby causing the tip to bend and making it impossible to penetrate the lesion. In one embodiment shown in FIGS. 11A - 12D, a laser (not shown) is used to form a rough surface, i.e., a rough surface 154, on the solder / weld joint 156 at the distal tip of the guidewire 150. Commercially available lasers such as fiber lasers enable a focused spot of about 0.0254 millimeters and can provide a random or densely stitched pattern as shown in FIGS. 11A and 11B, or provide spaced-apart dimples 158 as shown in FIGS. 12A - 12C. The dimples 158 resemble the dimples on the surface of a golf ball and can have a specific spacing and pattern. In one embodiment, the laser has a diameter of 0.0254 millimeters and forms a series of dimples 158 spaced 0.0254 millimeters apart from each other. In another embodiment, the dimples 158 have a diameter in the range of 0.0127 millimeters to 0.127 millimeters and have a spacing between the dimples 158 in the range of 0.0127 millimeters to 0.127 millimeters. In another embodiment, the laser has a diameter of 0.0254 millimeters to form the rough surface 154 and forms dimples 158 spaced 0.0127 millimeters apart. It is also possible to provide a larger spacing between the dimples 158 to provide a mechanical advantage in certain clinical cases.The laser may be programmed to provide an area on the solder / weld joint 156 that remains untouched (i.e., smooth) depending on the application. The pattern to be removed (dimples 158) can be easily modified by simply changing the laser frequency, the lattice spacing (the dimples 158 spaced apart from each other), or by programming each dimple to achieve an optimal configuration.

[0035] The dimples 158 also have a depth dimension 160 and a diameter 162 as shown in FIG. 12D. Preferably, the dimples 158 have a depth dimension 160 in the range of 0.5 μm to 1.5 μm, more preferably 1.0 μm.

[0036] Similarly, the radius dimension 162 of the dimples 158 may be in the range of 0.3 μm to 6.0 μm, preferably 2.0 μm to 4.0 μm, more preferably 3.0 μm. In this process, with the wire tip placed at the jig end, a commercially available fiber laser is used to selectively soften the solder / weld surface of the guide wire tip towards which the beam is directed to create dimples. This process is carried out with a very high pulse rate of the laser that provides concentrated heating only at the targeted location of the beam, without destroying the structural integrity of the solder or the weld of the solder / weld material. In one embodiment, the cycle time for the laser process is 50 ms, which allows for a modified tip texture that is acceptable in a production environment. Higher or lower laser cycle times may be acceptable depending on the composition of the solder / weld as well as the size and depth of the dimples.

[0037] In addition to using a commercially available laser, the dimples 158 can be formed by other processes such as bead blasting, chemical etching, or mechanical impact as long as the integrity of the solder / weld joint 156 is maintained.

[0038] The dimples 158 can be formed on the surface of the solder / weld joint 156 after forming the solder / weld joint 156 at the distal tip 152 of the guide wire 150. Alternatively, the solder / weld joint 156 can be manufactured at the component level and then the dimples 158 can be formed on the surface of the joint. Thereafter, the solder / weld joint 156 having the pre-formed dimples 158 can be attached to the distal tip 152 of the guide wire 150.

[0039] As shown in FIG. 12E, an experiment was conducted to compare the lesion crossing performance of the laser-dimpled guide wire with that of commercially available guide wires. To determine the time it takes for the guide wire to cross the lesion, tests were performed on a clinically relevant chronic total occlusion (CTO) model. The round dots represent the time in seconds required for the guide wire to cross the lesion, and the triangular dots represent the guide wires that were unable to cross the lesion. As can be seen from FIG. 12E, the laser-dimpled guide wire performed substantially better than commercially available guide wires and wires without dimples with respect to consistent better crossing times and attempts without failure to cross the lesion.

[0040] Coils with different cross-sectional shapes Generally, the distal end of the guide wire must have a small support shape in order to be flexible enough for passage capabilities. Thus, the distal end of the core wire is ground (tapered) and covered with a coil to make it flexible and non-traumatic (see, for example, FIGS. 2-3). The coil also helps to maintain the outer diameter of the guide wire in a consistent state. Prior art coils are formed from wires having a circular cross-section (FIG. 13) and are cut with a laser.

[0041] For next-generation guide wires, a good torque response that does not adversely affect the bending stiffness of the guide wire is an important functional attribute.

[0042] In the present invention, multiple wire cross-sections were designed to improve the functionality of the guide wire. Finite element analysis (FEA using commercially available ABAQUS software) was performed on these guide wire cross-sections to identify the effects of different cross-sections on torque response and bending stiffness.

[0043] The present invention enhances the torque property of the guide wire without adversely affecting the bending stiffness and functionality thereof by using coils with different cross-sectional shapes. As shown in FIGS. 15A to 23B, different embodiments include cross-sections of circular 178 (prior art), I-beam shape 180, vertical rectangle 182, vertical ellipse 183, square 184, vertical hexagon 186, horizontal hexagon 188, flat shape 190, and horizontal ellipse 192. From the FEA, it has been demonstrated that by removing more material from the neutral axis (N.A.) of the coil wire, the torque property can be enhanced while reducing the bending stiffness. Coils with different cross-sections were fabricated, and torque was applied while maintaining other parameters such as the material and volume of the wire of the coil constant. For this study, the coil material under consideration was 304V stainless steel. FIG. 14 shows the material properties of 304V stainless steel. To maintain the volume constant, the cross-sectional area, length, nominal diameter, and pitch of the wire were kept constant.

[0044] Coils with different cross-sections are shown in FIGS. 15A to 23B with the same length, pitch, average diameter, and cross-sectional area (dimensions enlarged up to 100). FIG. 24 shows the torque response of single-strand coils with different cross-sections analyzed by ABAQUS using the provided material properties. The torsional stiffness of the I-beam shape is the highest, followed by the rectangular cross-section and the vertical elliptical cross-section in that order. The wire with a peanut-shaped cross-section also showed high torsional stiffness (FIG. 24). FIG. 25 shows the bending stiffness of coils with different cross-sections. Therefore, by changing the wire cross-section of the coil from circular to I-beam shape, the torque response was increased by 250% while reducing the bending stiffness by 50%. Considering the constraints due to manufacturing, dimensions, and tolerances, the I-beam shape, peanut shape, vertical rectangle, and vertical ellipse shapes according to the application or other limitations are more preferable than the conventional round cross-section coils.

[0045] In FIGS. 15A to 23B, the shapes and sizes of coils 178, 180, 182, 183, 184, 186, 188, 190 and 192 are for illustration purposes, and are for ensuring that parameters such as the length, pitch, average diameter and cross-sectional area of the coil wire are constant for test purposes.

[0046] Coils 180, 182, 183, 184, 186, 188, 190 and 192 can be used together with the guide wire 30 shown in FIGS. 2 to 6, and can be used as either an inner coil or an outer coil.

[0047] Guide Wire Tip Forming Tool - Micro J Guide wires are sold either in a straight or pre-formed "J" shaped configuration. Generally, the distal tip of the guide wire is in a micro "J" shape to assist in maneuverability. The wire can be shaped by the manufacturer or physician using a forming tool provided with the guide wire. Shaping by the manufacturer is a more repeatable and automated process that does not compromise the integrity of the wire. The majority of users prefer straight wires and shape the tip themselves. Guide wire products provide a mandrel and introducer to assist the physician in wire shaping.

[0048] It has been found that users do not have good control in the method of shaping the wire and can easily damage the wire. From testing, it has been found that there are optimal angles (i.e., about 20° to 30°) and distances from the tip (2 to 3 mm) that can significantly assist wire performance. Even if physicians know what specifications they desire in terms of bending based on size, most physicians do not know where the optimal dimensions close to the intended ones are. Also, when physicians perform shaping, there is a higher risk that the wire will lose its integrity and functional performance.

[0049] In the embodiments shown in FIGS. 26-30, the micro "J" shaping tool can be shipped with a guide wire or sold as a separate accessory. This shaping tool has pre-determined existing slots if the physician can determine the angle and distance from the tip to form a bend in the shape of a micro J. This tool has a universal design and is also compatible with all of the manufacturer's guide wires.

[0050] In the embodiments shown in FIGS. 27A-30, the forming tool 200 includes a first member 202 and a second member 204, and a plurality of cavities 206 having different depths and shapes. A channel 208 extends through the wall 210 of the first member 202, providing access for the distal end 212 of the guide wire 214. The second member 204 is slidably received within the first member 202, and a third member 205 is inserted into the slot 207 of the first member 202 to hold the second member 204 within the first member 204. The third member 205 can be adhesively or laser welded within the slot 207, but allows longitudinal movement or sliding between the first member 202 and the second member 204. A pair of springs 216 are spring biased to maintain the spacing tool 200 in the open position 218. In the open position 218, the distal end 212 of the guide wire 214 can be inserted through the channel 208 and advanced into one of the cavities 206 (see FIG. 27B). To form the micro J tip, the user pushes the end of the second member 204 in the direction of the arrows in FIGS. 28A and 28B, thereby overcoming the spring force of the springs 216. As shown in FIGS. 28A-30, the second member 204 slides relative to the first member 202 to the closed position 220. In the closed position 220, the cavities 206 are moved relative to the channel 208 such that the distal end 212 of the guide wire is bent at a predetermined angle and the bend sets a predetermined length from the end 222 of the distal end 212. When the user releases the pressure on the end of the forming tool 200, the springs 216 snap open to allow the guide wire 214 to be removed from the cavity 206 and move the first member 202 to the open position 218. The cavities 206 exhibit bends at angles of 25° and 30°, but a bending range of 5°-40° is contemplated. Similarly, the bend length from the distal end 220 to the unbent portion of the guide wire 214 is preferably 1 mm or 2 mm, but the length may range from 0.5 mm to 5 mm.

[0051] Parabolic grinding profile In another embodiment of the present invention, the distal portion of the guide wire has a reduced cross-section so as to be more flexible when navigating tortuous blood vessels such as coronary arteries. The distal portion of the guide wire must be flexible and pushable, i.e., the distal portion can bend and be maneuvered through a tortuous artery, and must also have some rigidity so that it can be pushed or advanced through the artery without bending or twisting. The prior art guide wire is shown in FIG. 31 and has a distal portion consisting of a tapered section and a non-tapered core. The resulting bending stiffness is shown in the graph of FIG. 33, where the bending stiffness decreases at the location of each taper and remains constant along the non-tapered core. The tapered distal portion of the prior art guide wire in FIG. 31 gives a sharp change in bending stiffness, which can reduce the physician's tactile sensation when advancing the guide wire through a tortuous anatomical structure. In fact, in some prior art guide wires, the sharp change in bending stiffness can cause the distal tip of the guide wire to twist or become detached into a bifurcated blood vessel as schematically shown in FIG. 34. Detachment can be dangerous for the patient in that the artery may be damaged or punctured. Importantly, it is preferred to maintain the outer diameter of the core as distal as possible to maintain torque. Each tapered section loses significant torque when advancing the guide wire through a tortuous blood vessel.

[0052] In light of the present invention, the parabolic distal portion 232 of the guidewire 230 is shown in FIG. 32, where a significant portion of the distal portion has been ground to form a continuous taper. More specifically, the continuous taper is formed by a parabolic grind along the parabolic distal portion 232 of the guidewire 230. The parabolic grind provides a smooth, curvilinear transition along portion 232 that maintains a very flexible yet linearly varying stiffness, as shown in the graph of FIG. 33. The parabolic distal portion 232 is not only flexible, but it has a linearly varying stiffness, thereby providing excellent torque and tactile feedback to the physician when advancing the guidewire through tortuous anatomical structures. The non-curved taper portion 234 (not the parabolic ground portion) is located on the guidewire 230 distal to the parabolic distal portion 232 and it provides a reduction in bending stiffness and a linearly varying bending stiffness, as shown in the graph of FIG. 33.

[0053] Bending stiffness can be measured in a variety of ways. A typical method of measuring bending stiffness involves fixing a portion of the sample being tested immovably to a block, extending a part of the sample from the fixed block, and measuring the amount of force required to deflect the end of the sample a predetermined distance from the fixed block. Similar techniques can be used by fixing two points along the length of the sample and measuring the force required to deflect the middle of the sample by a fixed amount. One of ordinary skill in the art will understand that there are numerous variations to these basic methods, including measuring the amount of deflection resulting from a fixed amount of force applied to the free end of the sample. Other methods of measuring bending stiffness may produce values in different units of different overall magnitudes, but it is believed that the overall shape of the graph remains the same regardless of the method used to measure bending stiffness.

[0054] The parabolic grinding profiles of a guide wire with a 0.014-inch diameter are shown in FIGS. 35 and 36, respectively. The guide wire of FIG. 35 has a tip load of 11 grams, and the guide wire of FIG. 36 has a tip load of 14 grams. The unit of the scale on the Y-axis is inches, and the X-axis is centimeters. In both FIGS. 35 and 36, the two parabolic grinding profiles are separated by a core wire segment of uniform diameter. More specifically, each graph shows a first parabolic grinding profile that starts at approximately 23.1 cm from the distal tip of the guide wire and ends at approximately 17.9 cm from the distal tip. Further, each graph shows a second parabolic grinding that starts at approximately 4.8 cm from the distal tip. A core wire portion of uniform diameter is between the parabolic grinding portions, and there is a core wire portion of uniform diameter that starts at approximately 1.2 cm from the distal tip. The parabolic grinding profiles shown in FIGS. 35 and 36 have a linear change in stiffness, are flexible, and provide a guide wire that still maintains a high degree of torque relative to the distal end of the guide wire for navigating tortuous arteries and other blood vessels.

[0055] Using conventional materials and manufacturing methods, the parabolic grinding profile of the guide wire of the present disclosure may be formed. One skilled in the art can form the parabolic grinding profile disclosed herein using a computerized grinding machine.

[0056] Although the present invention has been illustrated and described herein with respect to its use as a guide wire, it will be apparent to those skilled in the art that the guide wire can be used in all blood vessels in the body. All dimensions disclosed herein are merely by way of example. Other modifications and improvements can be made without departing from the scope of the present invention.

Claims

1. an elongate core member having a proximal core portion, a distal core portion, and a tapered segment tapering from a proximal end configured to remain outside the patient's body to a smaller diameter toward a distal end configured to be advanced into the patient's vascular system; a radiopaque inner coil having a distal end and a proximal end, the radiopaque inner coil having a uniform outer diameter extending from the distal end to the proximal end of the radiopaque inner coil, the radiopaque inner coil being disposed over the distal core portion of the elongate core member; a non-radiopaque outer coil having a distal end and a proximal end, the non-radiopaque outer coil having a uniform inner diameter extending from the distal end to the proximal end of the non-radiopaque outer coil, the non-radiopaque outer coil being disposed over the radiopaque inner coil and the distal core portion of the elongate core member; a uniform sized gap defined by the uniform outer diameter of the radiopaque inner coil and the uniform inner diameter of the non-radiopaque outer coil, the uniform sized gap extending from the distal end to the proximal end of the radiopaque inner coil; A guidewire comprising: the distal end of the radiopaque inner coil and the distal end of the non-radiopaque outer coil are connected to the distal end of the elongate core member by a solder ball; the proximal end of the radiopaque inner coil is connected to the elongate core member and is not attached to the non-radiopaque outer coil; the proximal end of the non-radiopaque outer coil is attached to the elongate core member; the radiopaque inner coil contacts the elongate core member at least at the distal end of the radiopaque inner coil and at the proximal end of the radiopaque inner coil, and does not contact the non-radiopaque outer coil; one or both of the radiopaque inner coil and the non-radiopaque outer coil have a non-circular cross-sectional shape. Guidewire.

2. The guidewire of claim 1 , wherein the proximal end of the radiopaque inner coil is connected to the elongate core member by a first solder joint.

3. The guidewire of claim 2 , wherein the proximal end of the non-radiopaque outer coil is attached to the elongate core member by a second solder joint.

4. The guidewire of claim 3 , wherein the first solder joint is proximal to a solder ball and distal to the second solder joint.

5. The guidewire of claim 1 , wherein the radiopaque inner coil is formed from a single wire.

6. The guidewire of claim 1 , wherein the radiopaque inner coil is formed from multiple wires.

7. The guidewire of claim 1 , wherein the non-radiopaque outer coil is formed from a single wire.

8. The guidewire of claim 1 , wherein the non-radiopaque outer coil is formed from multiple wires.

9. 10. The guidewire of claim 1, wherein the radiopaque inner coil is made of a radiopaque material selected from the group of radiopaque metals including platinum (Pt), palladium (Pd), iridium (Ir), tungsten (W), tantalum (Ta), rhenium (Re) and gold (Au).

10. 2. The guidewire of claim 1, wherein the non-radiopaque outer coil is formed from a non-radiopaque material selected from the group of non-radiopaque materials including stainless steel (SS), cobalt-chromium (CoCr) and nickel-titanium (NiTi) alloys.

11. 2. The guidewire of claim 1, wherein the cross-sectional shape of either or both of the radiopaque inner coil and the non-radiopaque outer coil is any one of an I-beam, a vertical rectangle, a vertical oval, a square, a vertical hexagon, a horizontal hexagon, a flattened shape, and a horizontal oval.

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